Electric conductive polymer materials are used for electrodes of capacitors, electrodes of dye-sensitized solar cells, electrodes of electroluminescence displays. As such electric conductive polymer materials, polymer materials obtained by polymerizing a monomer(s) such as pyrrole, thiophene, 3,4-ethylenedioxy thiophene, aniline are known, and related techniques have been disclosed in Patent Literatures 1 to 3.
Patent Literature 1 relates to a polythiophene solution (dispersion), a method for producing the solution and use of a salt for an antistatic treatment of a plastic molding. It concretely describes a polythiophene dispersion, in which the polythiophene has a structure unit of 3,4-dialkoxythiophene, in the presence of a polyanion. It describes that the polythiophene dispersion is produced by oxidative polymerization of 3,4-dialkoxythiophene at a temperature of 0 to 100° C. in the presence of a polyanion.
Patent Literature 2 relates to an aqueous dispersion of a composite of poly(3,4-dialkoxythiophene) with a polyanion, and a method for producing the dispersion, as well as a coating composition comprising the aqueous dispersion, and a coated substrate having a transparent electric conductive film coated with the composition. It concretely describes an aqueous dispersion of a composite of poly (3,4-dialkoxythiophene) with a polyanion, which is produced by polymerizing 3,4-dialkoxythiophene by using peroxodisulfuric acid as an oxidant in an aqueous solvent in the presence of a polyanion.
Patent Literature 3 relates to a dispersion liquid including polystyrene sulfonic acid and 3,4-polyethylenedioxythiophene, in which the particle sizes of at least 90% by weight of particles are smaller than 50 nm, and an electroluminescent device including a hole-injection layer made from the dispersion liquid. It describes that the resistance of 3,4-polyethylenedioxythiophene can be increased without losing a desired hole-injection action by making the particle sizes of at least 90% by weight of particles smaller than 50 nm, in the dispersion liquid including polystyrene sulfonic acid and 3,4-polyethylenedioxythiophene.